Engine runs bad after view sec.

[nielsmobers]

The following: when my engine ('72 302) runs idle for more then 10 sec. it starts to misfire irregular. When I hit the gas two time it's gone and comes back when it idles for 10 sec. If I drive normaly it runs perfect. I've allready replaced the points and it didn't make any difference.

Niels

[mustangman65_79]

I hope u don't have the same problem with your car as I do.

I have bad valve guides, so when I go to start my car, it starts missfiring after about 5 sec of running.


Give some details about your motor. Rebuild? have u changed the wires? Spark plugs?

[nielsmobers]

As far as I know my engine hasn't been rebuild, I have a '72 Grandé with a 302 2v engine. The 10 sec. is probably a bit to short, it varies a lot, sometime it could be after more than a minute. Does your engine run fine when you drive?? I have my CO exhaust measured not long ago an it was perfect and the presure in the cylinder is also good... is it still possible that I have the same problem? (I hope not) Is there a methode to determine if I have the same problem?

Niels

[mustangman65_79]

Well, if it takes a minute or so, then it's more then likely not valveguides. I first try replacing your plug wires, for that they might be sparking when your motor heats up.

Go somewhere really dark, start up your car, open the hood, and see if u see a lightning storm.



But to me, sounds like it might be a wiring prob.

[PKRWUD]

Take the air cleaner off when it's idling, and listen for a dripping or popping sound coming from the carb. If the float is set too high, the extra fuel can flow over and create a missing/popping after idling for a few.

It could also be your plug wires. Make sure they aren't touching each other, specifically the wires going to plugs 7 & 8.

Take care,
~Chris